[Lf] [Fwd: LF: Counterpoise Experiment]

[Andre Kesteloot]

MarkusVester at aol.com wrote:

> Hi Jim,
>
>  thank you for reporting these very interesting experiments. I wonder if you
> could optimize the shielding effectiveness of the counterpoise by connecting
> it via a variable inductor to ground, thus inducing an adjustable
> opposite-polarity voltage to nullify the displacement current into the earth.
> If I remember right, the technique was shown in the circuit diagrams of SAQ's
> antenna system. - A few years ago, we applied the same principle to
> effectively neutralize a tetrode amplifier at 40 MHz, using its screen-grid
> lead inductance.
>
> My LF antenna is mostly above our roof, which has a thin aluminium
> vapor-diffiusion barrier beneath it. A while ago I found that explicitely
> connecting parts of the foil to TX ground reduced the antenna resistance from
> 32 to 30 ohms (and less noise-pickup from devices within the house). Judging
> from the large variations seen during frost periods, I believe a large part
> of the remaining loss is due to the capacitive coupling to nearby trees.
>
> 73
> Markus, DF6NM
>